Download ASeries A451 User Manual Interface Converter

User Manual
ASeries A451
Interface Converter
RS-232 RS-485 Multidrop
The interfacing specialists
A451 User Manual
Version 1.00
April 2000
COPYRIGHTS
All rights reserved. This document may not, in whole or part, be copied, photocopied,
reproduced, translated, or reduced to any electronic medium or machine readable form without
the express permission in writing from Alfatron Pty Ltd.
Copyright 2000 © Alfatron Pty Ltd
DISCLAIMER
Alfatron Pty Ltd has made every attempt to ensure that the information contained in this
document is accurate and complete. Alfatron Pty Ltd makes no representation or warranties of
merchantability or fitness for any particular purpose. Alfatron Pty Ltd reserves the right to make
changes to this document at any time, without notice. Therefore, Alfatron Pty Ltd assumes no
liability for damages incurred directly or indirectly from errors, omissions or discrepancies with
the hardware and the manual.
TRADEMARKS
All Company and Product names are trademarks of the Company or Manufacturer respectively.
WARRANTY
Alfatron warrants its products against defects in materials and workmanship for a period of one
year from receipt by the customer. All warranty is carried out on a return to depot basis unless
an alternative warranty coverage has been arranged.
WARRANTY EXCLUSIONS
The above warranty shall not apply to defects resulting from improper or inadequate
maintenance by the customer, unauthorised modifications or misues, operation outside the
environmental specifications for the product, damage due to power surges, lightening strikes or
any other phenomenon outside normal operational specifications.
Alfatron Pty Ltd ACN: 005 410 819
P.O. Box 4161
Unit 9/36 New St.
Ringwood VIC 3134
AUSTRALIA
Email: [email protected]
Web Site: www.alfatron.com.au
A451 User Manual
1.0
PRODUCT DESCRIPTION
The ASeries A451 is an RS-232 to RS-485 Multidrop interface converter using
standard RJ-45 Ethernet cabling on the RS-485 side. On the RS-232 side a
DCE/DTE switch is provided for easy reversing of the TD and RD signals.
The RS-485 port will support up to 32 drivers and 32 receivers over a cable
length of 1200 metres at speeds up to 115Kbps.Transient Protection is also
provided on the RS-485 lines.
Full Duplex (4 wire) or Half Duplex (2 wire) operation may be used on RS-485
and internal jumper settings permit the use of either 'standard' or 'crossed'
Ethernet cables. The layout of the A451 is as follows:
DCE / DTE
Selection
Power
Jack
RS-232 RD
(Green)
RS-232
Port
RS-485
Connectors
ON
SW1
RS-485 RD
(Green)
DIP Switch
Figure 1 - A451 viewed from all sides
2.0
INSTALLATION
Before installing the A451 please make sure that the DIP Switch settings are
according to the requirement of the RS-485 target device. It is also important
to select the RS-232 port as either DCE or DTE.
Make sure that all cables are terminated and then insert the power plug into
the jack socket and turn the power ON. The A451 is now ready for use.
2.1
LED indicators
The LEDs will operate only if DIP Switch 7 is set to the 'ON' position.
The RD (RS-232) LED indicator will flash each time data is being received by
the Serial RS-232 Port. The RD (RS-485) LED indicator will flash each time
data is being received by the RS-485 Serial Port.
These LEDs will not operate at any other time.
1
A451 User Manual
3.0
INTERFACE APPLICATION NOTES
3.1
About the RS-232 Port
The RS-232 connection is switch selectable as either DTE or DCE. For
connection to a standard PC with a straight through serial cable, select DCE.
When operating the A451 without the power adapter it is necessary to connect
the CTS/RTS and DTR/DSR signals as the power is drawn from these lines.
In most applications, it is necessary to connect all of the commonly used pins
on the RS-232 port ( i.e. 1, 2, 3, 4, 5, 6, 7, 8 and 20 on a DB25 interface ).
3.2
About the RS-485 Port
The RS-485 port may be configured for either a 4-wire or a 2-wire network.
This is done simply be choosing the appropriate jumper setting on the connector
JP1 located behind the RJ-45 sockets, as follows:
2
Pin
1
2
3
4
5
6
7
8
Description of Signal
Transmit Data Plus (TD+)
Transmit Data Minus (TD-)
Receive Data Plus (RD+)
Receive Data Minus (RD-)
Ground
Ground
1
Pin
1
2
3
4
5
6
7
8
Description of Signal
Receive Data Plus (RD+)
Receive Data Minus (RD-)
Transmit Data Plus (TD+)
Transmit Data Minus (TD-)
Ground
Ground
1
Pin
1
2
3
4
5
6
7
8
Description of Signal
(RD+) and (TD+)
(RD-) and (TD-)
Ground
Ground
1
JP1
Standard 4-wire
(Factory Default)
JP1
Crossed 4-wire
Configuration
JP1
2-wire
Configuration
A451 User Manual
3.3
Other RS-485 Considerations
When installing an RS-485 2-wire network the RS-485 transmitter must be
controlled by the RS-232 serial device. This transmitter may be controlled by
either the RTS/CTS or DTR/DSR signals.
If the RS-232 side is using software to control devices then it may require a
local echo of what it transmits, if so, turn DIP Switch 6 to the 'OFF' position.
If the distance of the RS-485 device is less than 100metres then it is not
necessary to terminate the RS-485 bus.
3.4
Using A451s as RS-232 Line Extenders
A pair of A451s may be used to extend the distance at which RS-232 data is
transmitted. The A451s are connected via their RS-485 ports to take advantage
of the greater data transfer distances achievable with RS-485.
The following examples show how to connect two A451s together via their
RS-485 ports using various cable types. Note that the internal jumper JP1
must be set as per these diagrams.
Example 1:
1
Using a Standard RJ-45 Ethernet Cable
JP1
1
JP1
1
JP1
Straight Through Cable
A451
Socket
Example 2:
1
A451
Socket
Using a Crossed RJ-45 Ethernet Cable
JP1
Crossed Cable
A451
Socket
A451
Socket
Note: Using a Crossed Cable requires no changes to the Factory Set JP1
3
A451 User Manual
4.0
CONFIGURATION OF THE RS-485 PORT
4.1
RS-485 DIP Switch Settings
DIP Switch
Function
1
2
3
4
5
on
off
off
off
off
RS485 transmitter Enabled when DTR/DSR is High
off
on
off
off
off
RS485 transmitter Enabled when RTS/CTS is High
off
off
off
off
off
RS485 transmitter ALWAYS Enabled
off
off
on
off
off
RS485 transmitter NEVER Enabled
off
off
on
on
on
Monitor Mode
DIP
Switch
Setting
Function
OFF
RS485 receiver always enabled (local echo for 2-wire RS485)
ON
RS485 receiver enabled only when RS485 transmitter
disabled
OFF
LEDs always OFF. Saves power in 'non powered' operation
ON
LEDs indicate RD/TD Data Flow
OFF
No termination on RS485 receiver
ON
120ohm termination on RS485 receiver
6
7
8
4.2
Factory Default RS-485 DIP Switch Settings
4
RS-485 Transmitter ALWAYS enabled
RS-485 Receiver ALWAYS enabled
(local echo for 2-wire RS-485)
LEDs indicate RD/TD Data Flow
No Termination on RS-485 Receiver
A451 User Manual
5.0
INTERFACE PORT PIN ASSIGNMENTS
5.1
RS-232 Serial Port Pinout
5.2
Pin
Status
Set for DCE
Set for DTE
1
2
3
4
5
6
7
8
20
Used
Input / Output
Output / Input
Linked to Pin 5
Linked to Pin 4
Linked to Pin 20
Used
Not used-Pulled High 4K7
Linked to Pin 6
Frame Ground
RD
TD
CTS
RTS
DTR
Signal Ground
DCD
DSR
Frame Ground
TD
RD
RTS
CTS
DSR
Signal Ground
DCD
DTR
Note:
Pins 4, 5, 6, 8 and 20 are pulled to the correct levels to allow a PC serial port to
operate under most conditions without any additional loopback connections.
Factory Default DCE/DTE Switch Setting
The Factory Default for the RS-232 Port is DCE.
5.3
RS-485 Serial Port Pinout
Pin number 1 for each RJ-45 connector is
shown here in the diagram. The two RJ-45
connectors are identical in pin assignment
and are connected in parallel.
Pin 1
Pin 1
The signals associated with each pin depend
on the configuration of the jumper JP1.
Please refer to Section 3.2 for these details.
5.4
Factory Default JP1 Jumper Setting
The A451 is shipped with JP1 set to
Standard 4-wire configuration as shown
here:
1
JP1
Standard 4-wire
(Factory Default)
5
A451 User Manual
6.0
CABLE GROUNDING
Alfatron recommends the use of shielded cable with all of its products. Shielding
reduces EMI Radiation and improves noise immunity. This helps minimise
interference to other equipment and will improve communications reliability.
6.1
RS-232 Cable Construction
The recommended cable construction is as follows:
6.2
Take the shield (surrounding cable wires) and solder it to the Frame
Ground (FG) pin. If FG is not available, use Signal Ground (SG) but in
this case always use a separate wire for ground which is connected at
both ends.
The shield must be connected at both ends of the cable.
RS-485 Cable Construction
While the RS-485 differential signal does not require a ground signal for
communication, we recommend that a ground wire is always connected in an
RS-485 Multidrop Network.
The longer distances available with RS-485 can present significant differences
in the voltage levels of the 'Ground' signal. This can lead to loss of data and at
the extreme, cause damage to the equipment.
7.0
CABLE EXAMPLES
7.1
RS-485 Cable from A451 to User Device
Pin
A451
Socket RJ-45
Standard 4-wire
(Factory Default)
6
Pin 1
Pin 2
TD+
TD-
Pin 3
RD+
RDTD+
Pin 6
RD-
TD-
Pin 7
GND
GND
RD+
User
Device
A451 User Manual
7.2
RS-232 Connection to a PC with a DB-25 Serial Connector
Shield
A451 Cable End
DCE
(DB-25 Male)
7.3
FG
RD
TD
CTS
RTS
DTR
SG
DCD
DSR
1
2
3
4
5
6
7
8
20
1
2
3
4
5
6
7
8
20
FG
TD
RD
RTS
CTS
DSR
SG
DCD
DTR
PC Cable End
DTE
(DB-25 Female)
RS-232 Connection to a PC with a DB-9 Serial Connector
Shield
A451 Cable End
DCE
(DB-25 Male)
7.4
RD
TD
CTS
RTS
DTR
SG
DCD
DSR
3
2
7
8
6
5
1
4
2
3
4
5
6
7
8
20
TD
RD
RTS
CTS
DSR
SG
DCD
DTR
PC Cable End
(DB-9 Female)
RS-232 Cable for Other Devices
Shield
A451 Cable End
DCE
(DB-25 Male)
FG
RD
TD
CTS
RTS
DTR
SG
DCD
DSR
1
2
3
4
5
6
7
8
20
FG
TD
RD
RTS
CTS
DSR
SG
DCD
DTR
User Device
Cable End
7
A451 User Manual
8.0
SPECIFICATIONS
RS-232C Port:
RS-485 Port:
LED Indicators:
Power Supply:
Asynchronous RS-232C/V.24
Select as DCE or DTE
DB-25 female connector
Speed capability dependant on cable length up to
64k bits per second
RS-485
Two RJ-45 connectors for multidrop setup
Switchable 120ohm Termination for RD line
Receive Data - RS-232 (Green)
Receive Data - RS-485 (Green)
9V (200mA) DC Power Adapter
Reverse polarity protection
Plug jack - 5.5mm outer/2.5mm inner diameter
Polarity is Outer Negative
Dimensions:
Weight:
Operating Temperature:
Stroage Temperature:
84mm x 58mm x 23mm
160 grams
10° to 35° C
0° to 45° C
All specifications subject to change without notice
8
N42
DECLARATION OF CONFORMITY
according to the European Commissions EMC Directive 89/336/EEC
We,
of,
Name of Manufacturer:
Address of Manufacturer:
Australian Company Number:
ALFATRON PTY. LTD
UNIT 9, 36 NEW ST.
RINGWOOD VIC 3134
AUSTRALIA
ACN: 005 410 819
declare under sole responsibility that the product:
Product Name:
ASeries RS-232 < > RS-485
Interface Converter
Model Number:
A451
to which this declaration relates is in conformity with the following standards:
CISPR-22 / EN 55022 class B
IEC 801-2 / prEN55024-2
IEC 801-3 / prEN55024-3
IEC 801-4 / prEN55024-4
EMI from Information Technology Equipment (ITE)
Electro Static Discharge Immunity
Radiated RF Immunity
Electrical Fast Transients Immunity